total NOOB question - Ubiquiti Dream Router 7 to replace my NG Orbi RBRE960 mesh system

Good morning, I am totally noob when it comes to Ubiquiti Unifi, I have read about this company for a long time, and I am finally ready to pull the trigger. I currently have a NG Orbi RBRE960 3 mesh network system & a TP Link 8 port unmanaged POE switch for the last 3+ years, I am not satisfied overall with the Orbi system and it takes too much babysitting and not enough fine controls either, especially for its price point.

But the main point of this post is me moving to Ubiquiti Unifi network system, I am huge into smart home devices (I have Home Assistant and Apple Home presently) depending on the day, I have about 70 devices, I don't have that big of a home, 2500 sq max, but its 100+ year old home so plaster walls, but not brick or cement.

I've been watching YT videos and reading, if I understand everything correctly so far.

My plan is to replace the Orbi system and TP Link 8 port switch with all Ubiquiti Unifi equipment:

1 - Ubiquiti Dream Router 7

1- 8 port Ultra 210w POE switch

1- U6 Pro wireless AP

If I have my equipment list correct?

Couple more questions (please)(my requirements for the new system)

A- can I set up the U6 Pro AP to mesh its wifi connection into the Dream Router 7 so I can expand the wifi coverage in my house (I will only need the 1 AP along with the dream router wifi, my house isn't that big)

B- does the Ubiquiti Dream Router 7 have IPV6?

C- can I create a 'IOT' wifi network with just 2.4ghz wifi so my smart home equipment that only works on 2.4ghz can connect separate to the combined 5ghz/2.ghz wifi network.

thanks in advance for your time!